Bone Abstracts

Introduction: Bisphosphonates are the most commonly prescribed type of medication for the treatment of osteoporosis. This treatment, however, is not without adverse effects. Several case reports and case series have indicated an association between a unique fracture type, so-called ‘atypical femoral fractures,’ (AFF) and prolonged bisphosphonate use.

Case report: We present a 77-year-old woman with no history of trauma, or associated with low-energy trauma, admitted to our clinic after three weeks of a left femoral fracture threated in Orthopedic Clinic. The patient was in our clinical observation since 1983 for hypothyroidism after thyroidectomy in treatment with 100 mcg LT4. In 2002, the patient was diagnosed with osteoporosis following the DXA examination. The bone mineral density (BMD) showed T-score at total lumbar spine: −4.0, total hip: −2.1, and left femur neck: −3.0. 25-OHD3 level varied between 17.69 and 5.54 ng/ml. TSH, FT4, and FT3 level was normal in time. Has been established treatment with risedronicum acidum 35 mg/week, Alfacalcidol 1 mcg/day and calcium 1000 mg/day. Annual DXA-BMD shows a slight increase of BMD; patient medical treatment has been changed in zoledronicum acidum and then on alendronicum acidum. The patient was in treatment with bisphosphonates over 10 years. An association between bisphosphonate long-term use and the occurrence of AFF has been suggested. This diagnostic has been supported and by the X-ray: femoral shaft region transverse fracture configurations, absence of comminution, a medial spike, localized periosteal thickening of the lateral cortex, and generalized thickening of the femoral cortices.

Discussion and conclusions: The causal relationship between prolonged bisphosphonate use and the occurrence of AFF has not yet been established. For the patient at high risk of fracture, it may be beneficial to continue bisphosphonate treatment beyond 5 years. For most people with osteoporosis, the proven fragility-fracture risk-reduction benefits of bisphosphonates outweigh the risks of AFF.